Set class_resource_max to @{pb}

Using "D&D 5th Edition by Roll20" is it possible to set the value of "class_resource_max" or "other_resource_max" equal to the character's competence? If I try to write @{pb} I don't get the desired result. It would also be useful to be able to add it to the "initiative modifier" field.

In my games using D&D 5e by Roll20, when I click the gear icon of the class/other resources there is a check box saying Use PB? and I just check that As far as I know, there isn't currently a way to add @{pb} to the initiative_bonus directly on the sheet currently. You can add + @{pb} to the initiative_bonus attribute but there is a sheet worker it seems that will come and overwrite that attribute. On the gear tab of the character sheet there is a way to add a whole number to Initiative Modifier But I don't see a way to alter the formula to add @{pb} for say a Harengon character. I'd be happy for someone to show my wrong on this point. I'd like to learn if there is a better way than adjusting that value each time the PB increases.

At this time you cannot put any kind of formula or attribute in the number of uses. But as Joshua indicated you can click the Use PB checkbox.  For others, if your DM has a Pro account they can set up a script that keeps it updated.  Otherwise I recommend making a "Leveling" guide, usually in the Abilities section on the bottom right corner, or in the Bio section of the character sheet, and it tells you what to update when. 

I never realized there was gear in the resource boxes, I assume it was added with the release of Tasha's manual; this solves the problem of skills related to the proficiency bonus. Too bad there isn't the possibility to do the same with the initiative bonus, I'm playing a Harengon Gloom Stalker and I have many bonuses to add manually; I actually applied the proposed suggestion, I wrote down the level to which to increase the various bonuses.